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Difficulty: HardWired and Wireless Network Issues

A network technician is responding to a support ticket regarding a workstation in a corporate facility that cannot access network resources. The workstation is connected to a wall jack via a patch cable, but the network interface card (NIC) LED indicators for link status remain completely dark. Running diagnostic commands shows an automatically assigned IP address of 169.254.14.88. The technician immediately begins running traceroute commands to distant subnets to locate the network layer drop point. Which of the following actions represents the most essential troubleshooting step that the technician overlooked?

  1. Inspect the physical layer connectivity, including patch cables, wall jack seating, and switch port link LEDs.Answer
  2. B
    Reconfigure the network DHCP server to handle hostname-to-IP resolution instead of leasing IP configuration parameters.
  3. C
    Replace the access layer connection point with an unmanaged switch to handle IP routing between separate corporate subnets.
  4. D
    Adjust the adjacent 2.4 GHz wireless access point to broadcast on channel 3 to avoid overlap with existing channel 1 deployments.

Answer

Inspect the physical layer connectivity, including patch cables, wall jack seating, and switch port link LEDs.
The correct action is inspecting physical layer connectivity. Unlit LED indicators on the NIC point directly to a physical layer failure (Layer 1), such as a bad patch cable, disconnected jack, or disabled switch port. Performing Layer 3 diagnostic tests like traceroute is ineffective until a physical link is verified.

Step-by-Step Solution

1
Analyze the observed physical symptoms on the network interface.
The dark LED indicators on the NIC indicate a lack of physical layer (Layer 1) signal/link established between the NIC and the switch port.
Before executing higher-layer diagnostic commands, physical connectivity must be verified.
2
Evaluate the current IP address configuration output (169.254.14.88).
The 169.254.x.x block indicates an Automatic Private IP Addressing (APIPA) assignment resulting from an inability to contact a DHCP server.
APIPA is assigned because the unestablished physical connection prevents DHCP traffic from reaching the network.
3
Identify the primary step bypassed in standard CompTIA troubleshooting methodology.
Checking physical layer indicators (link light inspection, cable test, port check) should precede running command-line utilities like traceroute.
Traceroute operates at Layer 3 (ICMP/IP) and will immediately fail when Layer 1 physical link is down.

Key Concept

Physical Layer Diagnostics and Troubleshooting Methodology
Estimated Time:2m 0s
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Topics

Wired and Wireless Network Issues

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